1. Field of the Invention
The present invention is directed to a gas laser excited with pulsed microwave energy of the type having a discharge tube terminated with Brewster windows conducted through the waveguide.
2. Description of the Prior Art
A gas laser is described in an article "Laser Generation by Pulsed 2.45 GHz Microwave Excitation of CO.sub.2," Handy et al., Journal of Applied Physics, Vol. 49 (1978), pages 3753-3756. According to this article, a standing microwave discharge is generated in a waveguide, with a glass tube penetrating the waveguide in the transverse direction and serving as a discharge channel for the laser discharge. Profiled wedges of electrically conducting material, which influence the field distribution, are arranged along its longitudinal direction. Excitation of the gas laser in this manner yields relatively low intensity values, because the glow discharge required for the excitation of the laser can be produced only in a relative short region of the waveguide. The achievable discharge zone is shorter than a half-wave of the exciting microwave energy in the waveguide. This is also the reason that the discharge channel in this known device is arranged transversely relative to the waveguide. An attempt is made in this structure to maintain the discharge in the region of the waveguide by specially shaping the wedges. This embodiment can realize only an extremely short excitation zone for the laser because of the limitations in the dimensions of the waveguide which must be observed. The laser energy obtainable in this manner is therefore extremely low.